19 Make then this song for yourselves, teaching it to the children of Israel: put it in their mouths, so that this song may be a witness for me against the children of Israel. 20 For when I have taken them into the land named in my oath to their fathers, a land flowing with milk and honey, and they have made themselves full of food and are fat, then they will be turned to other gods and will give them worship, no longer honouring me or keeping my agreement. 21 Then when evils and troubles without number have overtaken them, this song will be a witness to them, for the words of it will be clear in the memories of their children: for I see the thoughts which are moving in their hearts even now, before I have taken them into the land of my oath.
22 So that same day Moses made this song, teaching it to the children of Israel.
Matthew Henry's Commentary on Deuteronomy 31:19-22
Commentary on Deuteronomy 31:14-22
(Read Deuteronomy 31:14-22)
Moses and Joshua attended the Divine Majesty at the door of the tabernacle. Moses is told again that he must shortly die; even those who are most ready and willing to die, need to be often reminded of its coming. The Lord tells Moses, that, after his death, the covenant he had taken so much pains to make between Israel and their God, would certainly be broken. Israel would forsake Him; then God would forsake Israel. Justly does he cast those off who so unjustly cast him off. Moses is directed to deliver them a song, which should remain a standing testimony for God, as faithful to them in giving them warning, and against them, as persons false to themselves in not taking the warning. The word of God is a discerner of the thoughts and intents of men's hearts, and meets them by reproofs and correction. Ministers who preach the word, know not the imaginations of men; but God, whose word it is, knows perfectly.